The 30-year-old was hauled off after just 10 minutes after he suffered back spasms in the build-up to the game.
Mystery surrounded the nature of Marcelo's injury who left the field in tears.
The world would be watching the game today with the hope that the last 16 of World Cup is not robbed of another giant - Brazil after defending champions were kicked earlier today.
Should England fear Belgium?
The striker may well be rested for the mouth-watering clash against England after suffering a knock against the Tunisians. Training is conducted in English under Spanish coach Roberto Martinez, who spent a decade managing in England .
And the South American giants team doctor Rodrigo Lasmar claims the unspecified injury was caused by a hotel bed.
The Brazilian soccer federation said Marcelo had improved from its back problem but did not provide a timetable on his recovery.
There was good link-up play between Coutinho and his Barcelona teammate Paulinho for the opening goal with the former having found space in midfield before finding the former Spurs man who lifted the ball over the goalkeeper. The important thing is that there is no injury. "He has responded very well to the physiotherapy treatment that we carried out in the stadium, but we have to wait 24 hours to make a better diagnosis".
Andy Murray column: Why my comeback was so emotional
Nick said before the match that he was the best guy for me to play on my comeback - I wouldn't agree with that. It was Murray's first competitive match for 11 months owing to a hip problem that required surgery in January.
Doctors will blame a soft mattress for an injury before admitting they made mistakes getting the players ready for the tournament in Russian Federation.
"There is no recovery period".
Trump tells Republicans to 'stop wasting their time' on immigration
His proposal drew immediate criticism from legal analysts and immigrant rights advocates who said it would violate the U.S. Trump suggested on Friday that some of the wrenching tales that have emerged from the borderwere fabricated by Democrats.
Will Brazil raise gold on July 15th?